Articles

For a long time the drupal_set_message() function has been a mainstay of Drupal development. You can use this function to print a message or an error response to a user. This is useful to do as it can be done almost anywhere before the final page rendering functions and will be printed into the same area of a Drupal page.

This has recently been deprecated in Drupal 8.5.0 and so I was looking around on how to do the same thing in a new way. Drupal now has a messenger service, powered by the class Drupal\Core\Messenger\Messenger. This can be included into your code using the following shortcut.

$messenger = \Drupal::messenger();

This can be used to print messages to the user. For example, to print a standard message with a blue background do the following.

$messenger->addMessage('Message printed to a user.');

This can be done in one line like this.

A while ago I was working on some changes to a website and came across a block of code that made me stare blankly at my screen. The website I was working on was a custom build website, created by another developer at the company I was working with at the time. I have never done a PHP:CSI on this site before but remember being so amazed at what I found at the time that I made a note of it for future reference. I have pondered recently how to approach the analysis of the code.

The code I found was in a method that inserted an item into a database table. For some reason that I can't fathom the developer had opted to not use auto increment ID's and has instead developed a method that essentially randomly decided on an ID number for the item.

I can't paste the entire block of code here, but I can include the region of code that made me scratch my head in bewilderment.

Colourising images is fairly simple to accomplish, especially using PHP's GD library. All we need to do is load an image, create a blank image of the same size in a particular colour and then merge the two images together.

In fact, we can do this entirely with the imagecopymerge() function, but creating a function to wrap all of this makes sense as well.

The following function takes an image resource (as created by imagecreatefrompng()), the red, green, and blue values of the colour, and the percentage to overlay the colour on top of the image. The percentage can be set to 0 for no effect and 100 to fully replace the image with the given colour.

From the drawers of "I didn't realise how complicated that was" I was wondering the other day how to draw a line using just pixels. This turned out to be more complicated than I thought.

Normally in PHP you would use the imageline() function to draw a line between two points. The following block of code creates and image and draws a white line from the coordinates 50x,50y to 200x,150y.

// Generate image resource with a width an height of 250 pixels.
$im = imagecreatetruecolor(250, 250);

// Create a colour.
$white = imagecolorallocate($im, 255, 255, 255);

// Draw a white line from 50x,50y to 200x,150y.
imageline($im, 50, 50, 200, 150, $white);

// Write the image resource to a file called line.png.
imagepng($im, 'line.png');

// Destroy the image resource.
imagedestroy($im);

This creates an image that looks like this.

Part of the process of putting a new site live can be moving DNS entries around. Prior to doing this it's a really good idea to sort out the Time To Live (TTL) of the DNS record so that when you do change DNS entries you aren't waiting around for a day for the DNS to sort itself out. Most DNS registrars will allow you to set your TTL down to a minute or so.

It's also very important to check the status of your DNS records to ensure that they have the correct TTL, usually a day before (and day of) the move.

You can check the TTL value of your A record with the host command. Change the value of the -t (type) flag to aaaa or cname to inspect different types of records.

host -a -t a www.hashbangcode.com

This will produce the following output. The TTL of the domain below is '125'.

Whilst it is possible to view the contents of an SSL cert from within most modern browsers I occasionally find the need to use the command line to find out the same information. I find this useful when renewing certificates as browsers can occasionally cache certificates for longer than expected, causing false results.

Following on from by previous post about sorting colours I decided to take another step towards sorting colours by segmenting the data to create a further dimension to the multi-dimensional array.

The array is already split into segments based on the hue of the colour, but we can further split this by separating out saturation and value into separate arrays within hue. To do this we set the saturation or value to be a constant and push them into separate arrays.

The new code looks like this. Please excuse the duplication of code here. This is just a simple example to show how the array is put together.

The last time I looked at sorting colours I had produced a nice band or sorted colours, but to do so I had essentially removed a third of the data from the colour information. This meant that there was no white or black colours in the band of sorted colours.

After a bit of thinking on how to solve this I hit upon a way of using a two dimensional array of colours to filter the colours into blocks. This would allow the missing colour information to be rendered correctly, and would only mean a small amount of work to allow it to work with the rendering function used in the previous examples.

Generating The Data

I could easily just generate every colour available and use that as the data. What I wanted to generate was a random assortment of colours that would represent the sort of data being produced by a system or other input.

I recently wrote a post about setting up a multi-site configuration setup using the Configuration Split module. That post was written after I did research into how to set up configuration splits and use them to create multi-site setups in Drupal. One thing I realised when doing that research was that although it's quite easy to get setup with that kind of setup, it's also easy to get it wrong and create a setup that really doesn't work.

Setting up a Drupal 8 site for a multi-site environment with a common configuration isn't too hard, it just requires a little bit of forethought and some planning to get things right. You need to have a default configuration in mind, and then think about how each site can override this configuration in different ways. I have seen it done wrong a few times recently and once you go down the wrong path, getting things back in line again can be a difficult.

The default configuration covers things like content types, vocabularies, fields, views, enabled modules, or anything else that would make up the structure of the site. Each sub-site would override this by adding configuration for theme components, custom block placement, or anything else that is custom to that site.